Engine.



Patented Feb. I8, |902.

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(No Model.)

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SPECIFICATION forming part of Letters Patent No. 693,782, dated February18, 1902.

l Application tiled August 7, 1901. Serial No. 71,170. (No model.)

To all whom it may concern:

Be it known that l, HERBERT H. BUFFUM, of Abington, in the county ofPlymouth and State of Massachusetts, have invented certain new anduseful Improvements in Engines, of which the following is aspeciiication.

This invention relates toreciprocating-pist0n motors, pumps,compressors, and other engines. Its object is to provide an improvedform of crank-pin bearing whereby wear is reduced, compactness secured,and easy-running qualities obtained.

Of the accompanying drawings, Figure l represents an axial section of anengine provided with my improvements. Fig. 2 represents an enlargeddetail transverse section of the crank-pin bearing. Fig. 3 represents asection in the lineS 3 of Fig. 2. Fig. A:represents a transverse sectionthrough a modied form of crank-pin bearing. Fig. 5 represents aplan viewthereof, partly in section.

The same reference characters indicate the same parts in all thefigures.

Referring to the drawings, l l represent the two opposed cylinders of asingle-acting engine having pistons 2 2,whicl1 operate through pitmen orconnecting-rods 3 3 on a single crank-pin 4. Instead of offsetting thecrankpin bearings on the ends of the pitmen, as is customary, I form theend of each with a segmental bearing-shoe 5, the two shoes beingopposite each other or in the same zone as the crank-pin, and each maybe, as shown, substantially as long as said pin. These shoes areseparated by sufficient angular space to permit of the angular movementsof the pitmen with respect to each other. Between the shoes 5 and thecrank-pin is located a split annular bushing or collar 6, whichpractically wholly surrounds the crank-pin and is loose, so as to becapable of rotating with respect to either the shoes 5 or the crank-pin4.

7 7 are split rings adjustable by means of bolts 8 S, surrounding theshoes 5 5 and serving to retain the pitmen in their proper relation tothe crank-pin. I have found by experiment that the presence of thebushing 6 in a bearing of this character greatly decreases friction andthat a bearing having the bushing will wear much longer and run ber ofbushings. In practice I have found.

that two or three bushings will give a better result than a singlebushing.

Since the thrust between the pitman-shoes 5 and the retaining-rings 7 ismuch less than that between the shoes and the crank-pin, I may employantifriction-rollers 9 9 between said rings and shoes, as shown in Figs.4 and 5, thereby permitting the rings to turn with respect to the shoeswith great ease.

l0 is a freely-movable roller-cage in which the rollers are mounted.

The invention is not limited to two pitmen, since a greater number maybe employed, the bearing-shoes 5 being correspondingly shortened inangular extent.

Adjustment for wear in both of the illustrated constructions is effectedby merely tightening the nuts 8. This contracts the rings '7, moves thebearing-shoes 5 radially inward, and contracts the bushing 6.

I claim- Ina crank-pin bearing, the combination of a crank-pin, acontractible bushing loosely surrounding the same, pitmen havingsegmental bearing portions embracing said bushing, a contractibleretainer surrounding said bearing portions, and adjusting means forcontracting the diameter of said retainer, the arrangement being suchthat the contraction of said retainer also eects the inward adjustmentof the bearing-shoes and bushing with respect to the crank-pin.

In testimony whereof I have affixed my signature in presence of twosubscribing witnesses.

HERBERT H. BUFFUM.

Vitnesses:

R. M. PlnnsoN, WILLIAM QUINBY.

